David Cameron is under pressure to defy his Liberal Democrat coalition partners and stage a referendum on Europe before the next general election.

Senior Conservatives urged the Prime Minister to hold a "mandate referendum" on his plan to re-negotiate the terms of Britain's EU membership as early next spring in a bid to halt the rise of Nigel Farage's rampant UK Independence Party.

Ministers warned they could not act without the support of Lib Dems as the Conservatives lack an overall Commons majority. However former Tory leadership contender David Davis said they should put it to a Commons vote and challenge Labour and the Lib Dems to vote against it.

"It would be very interesting for the Liberals - and indeed the Labour Party - to vote against giving the public a say on this matter," he told the BBC1 Sunday Politics programme.

"I think the politics of that for them are very difficult. If it was rejected by the other parties, I think that would actually cause a new dividing line in British politics. The Lib Dems are one sixth or one seventh of the coalition MPs. Should they have a veto on everything? I don't think so. Should they have the right to say 'no' to something which is so fundamental to the future of the country? I don't think so."

Mr Davis said staging the referendum to coincide with the elections to the European Parliament next May would be "an absolute Ukip killer". The Prime Minister could then go ahead with his plan hold an in/out referendum on Britain's EU membership once the re-negotiation was complete after the general election in 2015.

Foreign Secretary William Hague said the lack of an overall Conservative majority meant it was unlikely they could hold a mandate referendum before the general election, but did not rule out putting it to a Commons vote.

"It is likely in such a situation that our proposal would be defeated in the current House of Commons. That's a constraint but of course we haven't ruled that out, we will be considering the options on this," he told Sky News's Murnaghan programme.

Defence Secretary Philip Hammond suggested the Conservatives could publish a draft bill before the election, without a vote in the Commons, to underline their commitment to an in/out referendum in the next parliament.

"We are looking at doing that and I think that would be a very good idea. I would strongly support the idea of publishing a draft bill ahead of the election," he told BBC1's The Andrew Marr Show.